The last few northerly islands of the Åland archipelago, midway between Sweden and Finland, are just within sight. Otherwise, it is just ice, stretching as far as the eye can see. This particular type is known as nyis, or new ice – just a few days old and covered in a thin, shimmering layer of water. The surface bends and undulates slightly, crackling as bodies fly over it at a speed of 20km/h, all swaying gently from side to side with the hypnotic motion of practised long-distance skaters. They are traveling a total of 100km and are racing against the clock to get to safer, less exposed ice, but at the same time enthralled to be here in the first place.

Jenny Rosenius celebrating skating 3,000km for the year

“It was so amazing to be out on the north side [of the archipelago], but we were a little bit afraid, because if the wind turns, it can become very dangerous [as gaps can open up at the point where two ice sheets meet],” says Jenny Rosenius, one of the few women among Sweden’s adventure skaters, recounting the trip she made last March from Alören, on Åland’s far eastern side, to Havsvidden. Together with her partner, Mårten Ajne, and their photographer friend, Henrik Trygg, she covered 100km that day, taking her total to over 3,000km for the year – a milestone she celebrated with a bottle of Champagne.

Long-distance ice skating is nothing new in this part of the world. As far back as 4,000 years ago, people in southern Finland were strapping bones to their feet to slide over lakes. People in the Netherlands invented modern ice skates with steel edges in the 13th or 14th century, but it took a few hundred years for the sport to really spread. A craze then broke out across Europe in the 18th century, with Marie Antoinette and Napoleon Bonaparte among the sport’s enthusiasts. German philosopher Johann Wolfgang von Goethe even stated that skating on the ice “awakened noble thoughts”.

Mårten Ajne skating on Kalvfjärden in the Stockholm archipelago

In present-day Stockholm, the Stockholms Skridskoseglarklubb (SSSK) is an illustrious ice skating club of which Rosenius, Ajne and Trygg are members. It was founded in 1901 and, over the course of its history, its members have taken long odysseys, both into the waters surrounding the Stockholm archipelago and to bodies of water further north. In the brutal winter of 1940, a group of its members skated far out to the south of Stockholm, with drifting masses of pack ice – which form an uneven surface that makes skating impossible – forcing them to march on foot until they made it to Hartsö, an inhabited island more than 15km away.

Today, new communication technologies mean fanatics such as Rosenius, Ajne and Trygg can ring for help if they get lost. But it also allows them to find the best fresh ice to skate on – from the lakes of Skåne county in the far south of Sweden to those inside the Arctic Circle in the far north. “We have a community sharing ice observations, and with the calculations and the satellite images, we know when [the ice] will be perfect,” Rosenius explains. Sweden’s ice skating clubs are all connected via a website where enthusiasts share observations on the ice across the country. And as the sport draws many mathematicians and other academics, several of them have found ways to download and analyse the daily satellite images provided by NASA.

Information gleaned through this wide network has led the trio to embark on numerous ice skating trips, including to Ringsjön in the south of Sweden and to Lake Balaton in Hungary. On this particular trip to the north, the group rounded the entire northern side of the Åland archipelago – the Baltic islands between Sweden and Finland – on ice that had appeared only days earlier, and which days later had melted entirely. It was the first time anyone had been able to skate the route in years, perhaps even decades. “I don’t know when it was last possible,” says Trygg, his low voice surprisingly devoid of a Swedish accent.

A skater on Gråskärsfjärden in the Stockholm archipelago

A strong northeasterly wind, coming at the time of maximum ice cover, had held the sea ice up against the islands for a brief time, making it possible to skate on it even with nothing but open sea on one side. Normally, it is only safe to skate on ice between islands, where land on either side helps keep the surface rigid. “It was like a carpet; it was just coming and coming, and when it’s like that you skate all day,” Rosenius recounts.

After rounding Aspskär, one of the archipelago’s topmost islands, the group cut down towards Havsvidden as the way to the west was blocked by a wall of pack ice. Their route back was punctuated by rocky outcrops of pink granite, and along the way they stopped off at a cave with an opening that was half closed off by spectacular icicles. “The best part was up there, from the northeast point to the west. That was a long distance, and we just carried on and on,” Rosenius says. “It was amazing. We didn’t think it was possible.”

Rosenius, who has been skating intensely for 12 years, is so obsessive about the sport that she gave up her job at Stockholm’s Vasa Museum so that she could partake in it throughout the winter; whenever and wherever the ice was good. Like Trygg and Ajne, she has a water-tight backpack, which contains a change of clothes and essential safety equipment, permanently packed throughout the winter season, so that when they learn of freshly frozen ice, they can get there within hours. “Last winter it was a fantastic year, and I managed to skate 3,600km,” Rosenius reveals. “If there’s a window coming with seven days of magnificent ice, then we skate for seven days.”

Ice skating in Sweden

Travelling these sorts of distances requires Rosenius to be acutely aware of her own movements – a skill she built up over a decade as a ballet dancer. “It’s the same concentration on small, small muscles in the feet that allows you to have good technique; otherwise it’s a very, very big effort,” she says. “I often go with very strong men, and they have a different physique. If you have the wrong technique, you get very tired.”

While Rosenius skates primarily for the enjoyment she derives from the experience, Trygg and Ajne bring a competitive energy – documenting every trip, counting each kilometre and seeking out places that others wouldn’t dare to go for fear of potentially getting their calculations wrong and falling through the ice or being stranded. Trygg has been skating on thin, natural ice for 25 years and Ajne for 35, and their wealth of cumulative experience helps them judge when a stretch will be passable or if it’s too dangerous. “You need to time it,” Trygg says of strategising about the correct moment to venture out onto the ice. “And then you’re out there and it’s just barely [thick] enough. You can hear the tone [of the sound made when your skates meet the ice], how high the pitch is, and you can also feel it – it cracks, and it’s singing, and you just feel alive.”

“If there’s a window coming with seven days of magnificent ice…We skate for seven days.”

Deciding on the right spot requires complex calculations that account for each body of water’s size, latitude, elevation, wind protection, temperature and the speed and direction of the wind. “There’s a lot of hydrology and meteorology involved, and a lot of experience,” Trygg says. More often than not, what they are seeking is kärnis – congelation ice which, from a distance, has the colour and sheen of an onyx gemstone, but up close is entirely translucent, providing a dizzying view to the lake floor below.

Once skaters glide out onto the ice that’s less than five centimetres thick, steely concentration is required. For instance, when the ice starts to thin, the pitch of the blades becomes higher and higher – a warning from Mother Nature to stop or change direction. “When you’re in the front and you’re showing the way, then you have to be alert every second,” Trygg says. “You can see if the ice is changing, you can hear if the ice is changing, you can feel if it is starting to flex a little bit more.”

Henrik Trygg on Lake Vättern

But despite such planning and preparation, the activity can be unpredictable – which is part of what makes it so thrilling. Last winter, Trygg and Ajne were 20km out in the centre of Lake Vättern, Sweden’s second largest lake, when the wind suddenly shifted. “When we were on the way back to shore, we noticed that the whole ice sheet on the lake had started to drift and we were on it. And when we were just 100m from shore we saw the ice drifting apart, so we had to get to a really high speed and just jump about one and a half metres onto solid ice. Just seconds later there was 15m of open water [between the ice sheet and land].”

The rate of global warming is expected to be rapid in Sweden. Before too long, it may be hard to find good winter ice on Vättern and Lake Vänern, Sweden’s largest lake. It is already harder to skate in the archipelago in the winter compared to decades past. Trygg points to an expedition that members of their Stockholm skating club made in the 1950s, when they skated 100km from Sweden to Åland across the Åland Sea. “That’s impossible now,” he reveals. “Although you could maybe skate and then swim a little bit, and then continue skating.”

Anna Eklund, a hydrologist at the Swedish Meteorological and Hydrological Institute (SMHI) – the country’s state weather forecaster – has been studying the data – some of which goes back more than 100 years – on the freeze and ice break-up of Sweden’s lakes. According to her, the pattern is clear. “We can see that the freeze dates become later and later and the break-up dates earlier and earlier,” she says. “And we can see that in the southern parts of Sweden it is more common now to have years without ice in the lakes.”

A long-distance ice skater

Today, Mälaren, a lake which meets the sea at Stockholm, has ice cover for nearly three months on average each year. But over the next 20 to 30 years, SMHI expects this to fall to two, and by the end of the century to just one. Vänern presently still freezes over most years. But by 2032, SMHI expects it to be ice-free every other year, and towards the end of the century it will only freeze over once every six years. “I’ve noticed a difference,” Trygg says on the effect that increasing temperatures have had on the country’s ice. “But it’s also very different from winter to winter. Five to eight years ago, we had two or three winters in a row that were really cold and then we had four winters that were mild.”

For now, though, the waters around Stockholm are ideal for skating enthusiasts, as the temperature dips above and below freezing point through much of the season, meaning the ice is frequently renewed. “I actually think Stockholm is a paradise, because we always have this ice around the corner,” says Rosenius.“It’s magnificent when you manage to skate inside Stockholm, inside your own city.”

Joakim Malm, who runs Iceguide, a Stockholm-based tour company, says the capital’s “10-stage skating season” means there is almost always fresh ice available, with small shallow lakes freezing in the first stages, followed by the bigger lakes, then Mälaren and finally the sea around the archipelago. “The average winter temperature is -3°C to -5°C, and quite often the temperature is above freezing. From an ice skating point of view, it’s a benefit to have the weather going back and forth.”

Skating on Lake Dellen in Hälsingland

Malm’s team of 25 guides takes everyone from complete beginners to experienced skaters far out onto Mälaren or to explore the archipelago. “We’ve had people who have never seen ice apart from floating in a drink,” he says. “The beginners’ tour is not about distance [or] speed. It’s about sharing a one-of-a-kind experience. I see so many wet eyes and so many hugs from people that we have taken out on natural ice.”

Be prepared, though. Chances are a small taste of what draws people like Rosenius, Trygg and Ajne back to the ice each year won’t be enough. “You can be out on a big lake, where you don’t see any shore and the sun is setting and it’s completely quiet, no wind, no anything,” Trygg says, attempting to put the experience into words. “It can be very meditative when you just go on and on, hour after hour, and the scenery’s changing all the time. It is very fulfilling, to say the least.”

Indeed, once you’ve heard the melodic tone of ice so thin it can barely hold a person, it’s hard to forget its siren call.